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mirror: fix throttling delay calculation 

The throttling delay calculation was using an inaccurate sector count to
calculate the time to sleep.  This broke rate-limiting for the block
mirror job.

Move the delay calculation into mirror_iteration() where we know how
many sectors were transferred.  This lets us calculate an accurate delay
time.

Reported-by: Joaquim Barrera <jbarrera@ac.upc.edu>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Paolo Bonzini 2014-03-21 13:55:18 +01:00 committed by Stefan Hajnoczi
parent dc6fb73d21
commit cc8c9d6c6f
2 changed files with 16 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
block/mirror.c
View File

@ -139,11 +139,12 @@ static void mirror_read_complete(void *opaque, int ret)
mirror_write_complete, op);
}
static void coroutine_fn mirror_iteration(MirrorBlockJob *s)
static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s)
{
BlockDriverState *source = s->common.bs;
int nb_sectors, sectors_per_chunk, nb_chunks;
int64_t end, sector_num, next_chunk, next_sector, hbitmap_next_sector;
uint64_t delay_ns;
MirrorOp *op;
s->sector_num = hbitmap_iter_next(&s->hbi);
@ -231,7 +232,12 @@ static void coroutine_fn mirror_iteration(MirrorBlockJob *s)
nb_chunks += added_chunks;
next_sector += added_sectors;
next_chunk += added_chunks;
} while (next_sector < end);
if (!s->synced && s->common.speed) {
delay_ns = ratelimit_calculate_delay(&s->limit, added_sectors);
} else {
delay_ns = 0;
}
} while (delay_ns == 0 && next_sector < end);
/* Allocate a MirrorOp that is used as an AIO callback. */
op = g_slice_new(MirrorOp);
@ -268,6 +274,7 @@ static void coroutine_fn mirror_iteration(MirrorBlockJob *s)
trace_mirror_one_iteration(s, sector_num, nb_sectors);
bdrv_aio_readv(source, sector_num, &op->qiov, nb_sectors,
mirror_read_complete, op);
return delay_ns;
}
static void mirror_free_init(MirrorBlockJob *s)
@ -362,7 +369,7 @@ static void coroutine_fn mirror_run(void *opaque)
bdrv_dirty_iter_init(bs, s->dirty_bitmap, &s->hbi);
last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
for (;;) {
uint64_t delay_ns;
uint64_t delay_ns = 0;
int64_t cnt;
bool should_complete;
@ -386,8 +393,10 @@ static void coroutine_fn mirror_run(void *opaque)
qemu_coroutine_yield();
continue;
} else if (cnt != 0) {
mirror_iteration(s);
continue;
delay_ns = mirror_iteration(s);
if (delay_ns == 0) {
continue;
}
}
}
@ -432,17 +441,10 @@ static void coroutine_fn mirror_run(void *opaque)
}
ret = 0;
trace_mirror_before_sleep(s, cnt, s->synced);
trace_mirror_before_sleep(s, cnt, s->synced, delay_ns);
if (!s->synced) {
/* Publish progress */
s->common.offset = (end - cnt) * BDRV_SECTOR_SIZE;
if (s->common.speed) {
delay_ns = ratelimit_calculate_delay(&s->limit, sectors_per_chunk);
} else {
delay_ns = 0;
}
block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, delay_ns);
if (block_job_is_cancelled(&s->common)) {
break;

2
trace-events
View File

@ -82,7 +82,7 @@ mirror_start(void *bs, void *s, void *co, void *opaque) "bs %p s %p co %p opaque
mirror_restart_iter(void *s, int64_t cnt) "s %p dirty count %"PRId64
mirror_before_flush(void *s) "s %p"
mirror_before_drain(void *s, int64_t cnt) "s %p dirty count %"PRId64
mirror_before_sleep(void *s, int64_t cnt, int synced) "s %p dirty count %"PRId64" synced %d"
mirror_before_sleep(void *s, int64_t cnt, int synced, uint64_t delay_ns) "s %p dirty count %"PRId64" synced %d delay %"PRIu64"ns"
mirror_one_iteration(void *s, int64_t sector_num, int nb_sectors) "s %p sector_num %"PRId64" nb_sectors %d"
mirror_iteration_done(void *s, int64_t sector_num, int nb_sectors, int ret) "s %p sector_num %"PRId64" nb_sectors %d ret %d"
mirror_yield(void *s, int64_t cnt, int buf_free_count, int in_flight) "s %p dirty count %"PRId64" free buffers %d in_flight %d"